Please fix: Scripts and styles are injected improperly

This plugin injects scripts and styles improperly. A plugin shouldn’t just echo the script tags itself into the document. All scripts and styles should be queued and registered to the WordPress dependencies object as individual dependencies accordingly.

Not conforming to this makes it difficult, if not impossible, for theme developers to disable script loading on pages that aren’t using the addthis widget.

Please refer to http://codex.ww.wp.xz.cn/Function_Reference/wp_enqueue_script

http://ww.wp.xz.cn/plugins/addthis/